[T10] Questions about SAS TX RX common mode return loss
Jiagongxian
jiagongxian at huawei.com
Sun Nov 22 17:28:33 PST 2015
HI All,
I have a question related to SAS TX RX common mode return loss.
According to the SAS 3r06, for 12Gbps TX, the common mode loss requirement is based on Table 47, -12 Gbit/s maximum limits for S-parameters at Its OR CTS, the common mode return loss SCC22 start at -6 dB at low freq. band, which is measured according to method based on Figure F. 19, using de=embedding to reach the connector footprint according to the the document ( Section F.11.4.4, Tx Rx connection S11 measurements at IT or CT).
Which means, after de-embedding, TX or RX return loss is mainly influenced by the connector, if the return loss of SAS connector is high than -6 dB at lower freq. band, it will make the return loss of the device can not meet the spec. of TX or RX side of SAS device. Unfortunately, the SAS connector requirement is defined in Table 7,which is start at -3 dB at low freq. band..
Compare Table 47 (return loss requirement of SAS device) and Table 7 (return loss of SAS connector ) , the common mode return loss of connector is about -3 dB at low freq. band, while the common mode return loss of SAS device is -6 dB at low freq. band, which make it is very hard for the device’s common mode return loss to pass -6 dB spec. at some low frequency band.
Is there anything wrong with my analysis ?
Best regards
Jia Gongxian/贾功贤
Phone: 0755-89651131
Email: jgxian at huawei.com<mailto:jgxian at huawei.com>
Huawei Technologies Co., Ltd./华为技术有限公司
Bantian, Longgang District,Shenzhen 518129, P.R.China/深圳市龙岗区坂田华为基地,518129
http://www.huawei.com
-------------------------------------------------------------------------------------------------------------------------------------
本邮件及其附件含有华为公司的保密信息,仅限于发送给上面地址中列出的个人或群组。禁
止任何其他人以任何形式使用(包括但不限于全部或部分地泄露、复制、或散发)本邮件中
的信息。如果您错收了本邮件,请您立即电话或邮件通知发件人并删除本邮件!
This e-mail and its attachments contain confidential information from HUAWEI, which
is intended only for the person or entity whose address is listed above. Any use of the
information contained herein in any way (including, but not limited to, total or partial
disclosure, reproduction, or dissemination) by persons other than the intended
recipient(s) is prohibited. If you receive this e-mail in error, please notify the sender by
phone or email immediately and delete it!
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.t10.org/pipermail/t10/attachments/20151123/a785500f/attachment.html>
More information about the T10
mailing list